This research will analyze the role of economic assimilation in determining older immigrants' economic status in the United States. The outcomes of major interest are income and wealth. The analysis will rely on longitudinal earnings histories for a random sample of older immigrants and native-born Americans who have completed most of their working lives. I will use a rich source of survey data on individuals: the Health and Retirement Study (HRS), with merged Social Security earnings histories. These data provide information on over 7,600 households with earnings information over a forty-year span. Comparisons of wealth between natives and immigrants will incorporate differences in expected Social Security benefits and pension benefits- two forms of wealth not measured in other studies of immigrants. This study will provide new insight into the assimilation process in two major ways. First, in contrast to analyses based on repeated cross- sections of the Census, my results will not be affected by nonrandom outmigration or differing population coverage across Census samples. Second, 1 will be able to follow individuals' progress over a very long time span--as much as 40 years--and thus obtain a rich characterization of the life-cycle path of assimilation. Comparisons of the HRS sample with earlier Census samples will allow a description of the characteristics most associated with outmigration and provide insight into the selectivity of immigrants.